Viscum album ? A possible treatment for Cancer ?

^ost V9rcoma ^ 'n mice and cell cultures. The tUrnour Ct'Ve *ract'on produced a 50% reduction in only q Slze (compared with controls) at a dose of 6?.Oon "5 ^9/Kg. An average molecular weight of n^eans an active dose of 8.3 x 10-ir> mols/g. (He also quotes a figure of 8.5 x 10-11 mols/g for the commercial preparation Iscador.) In testing the various fractions for the effects in producing tumour inhibition in vivo, toxic effects in vivo, inhibition of cell cultures and of both HeLa cells and amnion cells, there is little correlation between the presence or absence of the various effects from


'ntroduction
There are a number of reports in the literature? y a few of which are in English language?suggest- (He also quotes a figure of 8.5 x 10-11 mols/g for the commercial preparation Iscador.) In testing the various fractions for the effects in producing tumour inhibition in vivo, toxic effects in vivo, inhibition of cell cultures and of both HeLa cells and amnion cells, there is little correlation between the presence or absence of the various effects from fraction to fraction, suggesting a variety of different proteins with different properties. Some of the protein components were found to be strongly antigenic, since less than 10 fig induced rapid antibody formation in rabbits. Vester suggests that this may be less important in human patients with tumours who may have a reduced immunological response.
The denaturing effects of pH and heat were examined and it was shown that the in vivo tumour inhibiting effect was easily destroyed, the general toxic effect being increased in some cases. Denaturing has far less effect on the in vivo activity. The proteins responsible for the tumour inhibiting effect were thought to be unusually labile (Vester et al., 1968b).
The effect of one of the active fractions of Viscum album (No. 16) on an in vitro preparation of Yoshida ascites cells was examined, monitoring R.N.A. (ribonucleic acid) synthesis by the uptake of labelled uridine tri-phosphate. At an optimal dose it was reduced to 30%. Mild denaturation (2 hours at 50?C) of the fraction before testing enabled a smaller dose to produce the same effect, and at the optimal dose uptake was reduced to 25%. This was thought to be as a result of the loss of specificity for only certain parts Theories as to method of action 1. It is felt unlikely that the action of Viscum extract is primarily that of an antimetabolite or a mitotic poison because of the lack of correlation between the tumour inhibiting effects, the toxic effects and the inhibition of different cell cultures by the various protein fractions. In addition, there was a lack of the usual side-effects associated with cytotoxic therapy.
2. The stimulation of the immunological response of the organisms has been suggested. This is supported by the rise in antibody titre in rabbits, by the production clinically of a temporary leucocytosis and mild pyrexia and stimulation of the cell mediated response suggested by thymic enlarge-ment (see under toxicity). This may not be the whole explanation.
3. Vester postulates a direct effect on aberrant cell controlling mechanisms, using the model of Jacob and Monod (1961). In this model, nucleoproteins are thought to repress certain lengths of D.N.A. thereby maintaining differentiation, a characterist'c of cells not behaving cancerously. In a hybrid fish, Poeciliidae, known for its high rate of spontaneous tumour development, it is thought that nucleoproteins are unusually acidic, making their attachment to the D.N.A. less stable. This instability makes it difficult to maintain differentiation and may explain the high rate of spontaneous tumour formation. It is at the level of these processes that the mistletoe protein may act. This is supported by the following evidence:? (a) The structural similarity of the active fractions to histones. (e) The sensitivity to denaturation. The specific cancer inhibiting property becomes a general cytotoxic property. This is as one might expect in a protein claimed to have such an an extreme specificity of action.
Cancer Chemotherapy National Service Centre report The C.C.N.S.C. report finding preliminary activity in K.B. cell culture (human epidermoid carcinoma of the nasopharynx, in water) using crude extracts of Viscum album. An E.D. 50 of 0.74 /zg/ml was established. When tested on Sarcoma 180 in mice at optimal doses, T/C ratios of 56%, 60%, 51% and 54% were achieved in various trials. Further wo k was not done as the extract failed to achieve a T/C ratio of 42% or less (C.C.N.S.C. 1962).

Authors' results
We tested the claim (Vester 1968) that the growth of Crocker sarcoma 180 is inhibited by doses of Iscador 8.5 x 10-11 mol/g body weight, calculated on the assumption of an active component of molecular weight 60,000, to the effect that at the end of a tenday test period the Iscador treated mice carried tumours of 50% of the weight of tumours in control animals. Our results confirmed that doses of Iscador of the order of magnitude quoted by Vester do indeed have a tumour inhibiting effect (p<0.005), though our results suggest that the degree of inhibition may be somewhat less than 50%. The Crocker 180 Sarcoma, because of its lack of specific antigenicity, is not an ideal model with which to attempt to mimic the behaviour of spontaneous human tumours. A far better model may be the primary carcinogen-induced Humours but as far as we are aware, no work relating to Iscador has yet been carried out on tumours of this type.

Toxicology
Using an active fraction of Viscum album the L.D.50 was determined in mice and found to be about ten times greater than a therapeutic dose for this fraction (Vester, 1968;author's unpublished data Although the two groups have a similar stage d5 tribution, there is no account of a thorough randort1 isation procedure at the outset.

2.
At the lainz Hospital Vienna, Gunczler and Sal^ (1969) have used Iscador in the post operative trea' ment of carcinoma of the breast, stomach, rectum ai"1' colon.
Breast?257 treated patients aro compared with a cC trol group of 187. At 2 years there was a statistical' significant improvement of survival by about 8% t1' none at 5 years. The control groups were those patient operated on in a previous period when radical mastcc tomies were performed on all patients, whereas mar1' of the treated group had either partial resections 0 simple mastectomies. It could be argued that t1 difference at two years reflected only the severity 0 surgery.
Stomach?67 treated patients are compared to 1^ control patients. It is stated that the treated group cC1 tained more patients with poor prognoses. The five ye3 survival rate is over 10% higher in the treated gro^f but not statistically significant. It is interesting to no*' that, if only those with lymph node involvement ar' compared from each group the difference in five yea survival between the groups is over 20% and is stat 5 tically significant. Rectum?This phenomenon is repeated in the resul1 0 treating carcinoma of the rectum. There is only a very slight difference between the total groups. Of ?se with lymph node involvement five out of fourteen reated patients survived five years, but none of the

Conclusion
The evidence suggests that Iscador may well have useful therapeutic effect on tumours. This is supr ed by evidence of some activity in animal experints-It would also appear that this is not a 0n Slstentradical or curative treatment and the effects animal tumours is small compared with any cyto-Xpj-agents used at optimal doses.
'nically it is claimed, and this is to some extent Ported by animal experiments, that Iscador does not to S6SS side'effects inherent in the usual cytosti C a9.ents-'n fact, the reverse occurs. There is a ulation of the humoral and cell-mediated immuno- GUNCZLER, M., G. SALZER (1969) Neinhaus et al. (1970). The L.D.50 for the strain of mice used here was determined independently because of possible strain-specific differences in sensitivity.
The tumour used was a high passage Crocker 180 Sarcoma implanted in random bred male Balb/c mice. Animals were selected from a narrow weight range rather than age to ensure uniformity of dose level. A fragment of tumour (approx. 1 cmm) was subcutaneously transplanted in the right flank endeavouring to obtain uniformity of size of implant. After random selection into control of experimental groups, experi-mental animals were given daily I.P. doses of 0.15 ml of Iscador of different concentration.
On day 9 both control and experimental groups were killed and tumours dissected out for weighing.
The average weights of tumours from control and experimental groups were compared to determine the T/c ratio. (weights 30-33 g) Average weight of control tumours = .159 g Average weight of treated tumours = .086 g T/C ratio = 54% S.D. = .071 (x1?x?) = .073; t-1.72 p = 0.1
Results over all: Average T/C = 64% ? 15% Overall probability of achieving these results & chance p = 0.1 x 0.1 x 0.5 = 0.005 i.e. less than 1 in 200 Discussion: The optimal dose determined experimentally is abo' 0.15 ml of 0.2% equivalent to .11 mg (dry weigt1 compared to Vester's .153 mg for a 30 g mous Our dose though slightly less, is clearly of the sarf order of magnitude.
The overall probability is achieved by multiply^ individual probabilities. The results show a statistical significant inhibition of tumour growth, though degree of inhibition cannot be accurately assessed to the variability, and the relatively small degree 1 inhibition, which on the basis of the rate of growth oi1 represents about 1 day delay. It appears to achie1 T/C ratio between 50%-75%.

Conclusion
These experiments confirm that doses of Iscad of the order of magnitude quoted by Vester do indef have a tumour-inhibiting effect though they sug9e that the degree of inhibition may be somewhat le; than 50%.